The present disclosure relates to a hot nozzle for lateral spraying of plastic components. The hot nozzle includes a multipart nozzle body including a tip inset including a tip element having a tip section protruding outwardly beyond a circumferential surface of the multipart nozzle body into a molding plate.
Reference is made to WO 99/37 461 A1, US2002/0098262 A1 and EP 0186 413 A2 concerning the technological background.
It is often advantageous in plastic injection molding technology to spray plastic parts laterally, for example, perpendicularly or obliquely in relation to the demolding direction. For this purpose, so-called hot nozzles are used for lateral spraying. Those hot nozzles are also known as lateral spraying nozzles which comprise a nozzle body and tip elements. In order to achieve advantageous temperature control for the melt up to the surfaces of the article, the nozzle tips or tip elements need to be guided right up to the surface of the article.
It is further known to divide mold components, for example, die components, which enclose the nozzle body, so that the nozzle tips or the nozzle body can be mounted in the case of arrangements with multiple cavities. Such a state of the art is shown in DE 100 08 471 A1. This division is disadvantageous because a complex construction of the mold needs to ensure the necessary locking forces in order to prevent leakages.
That is why constructions of lateral spraying nozzles with tip elements appear to be advantageous which allow using undivided insets. This can occur, for example, with adjustable tip elements such as proposed in DE 197 42 099 A1, or with the help of a subsequent mounting of the tips in an integral nozzle body once the nozzle body has been mounted. See, for example, EP 1524091 A2 and DE 103 45 578 A1. In the case of the tip elements which are mounted in narrow fits, the fitting gaps will be tightly held after a period of use of incinerated plastic to such an extent that destruction-free dismounting is often not possible. The disadvantages of the adjusting mechanism are the filigree components which are partly wetted with the melt, and after prolonged use, do not allow any reliable adjustment or dismounting of the tips any more. The adjusting devices often do not permit any high force or pressure loads because they do not provide sufficient pressure area due to the limited overall space.
The tip elements mounted in the integral nozzle body usually need to be provided with a very small configuration in order to remain mountable. Moreover, mounting and/or dismounting is exceptionally difficult in the known systems and can often only be achieved after prolonged use by destroying the tips.
It is known from EP 0 447 573 A1 and DE 90 03 574 to arrange the nozzle body not in an integral manner but in a divided manner so that this difficulty is reduced. A holding ring is placed on a kind of base part, for example, see FIG. 1 of EP 0 447 573 A1, on the axial side of which guide tips are held with a clamping ring. Mounting and dismounting of the tip elements are still not simple enough. Moreover, the melt flow is also not guided in a leakage-free manner from the melt entrance into the nozzle body up to the gate on the article, since the melt can also axially escape from the base part and flow about the guide tips. Considerable difficulties can arise in dismounting the tip elements by the ambient solidified plastic compound. The solidified plastic compound needs to be removed laboriously at first. Alternatively, the hot nozzle can be dismounted with the still pasty plastic material.
One solution to the aforementioned problems is provided by DE 20 2008 005 073, which, on the basis of a concept of a divided nozzle body, further develops the state of the art as mentioned above in such a way that it is possible to house even relatively large tip elements in the nozzle body in a simple way and to simply mount and dismount them even after prolonged use. One relevant advantage of these nozzles is, therefore, that the tip inset can be installed by a pivoting movement from the separating plane of the mold. In this process, the at least one tip of the tip element easily reaches the surface of the article to be sprayed and, after complete mounting of all components, the melt flow is guided in a leakage-free manner from the melt entrance into the nozzle body up to the gate at the article. Relatively large locking forces can be realized by the chosen configuration of the nozzle body, so that a high level of leakproofness is achieved. After mounting the tip inserts, the sealing sleeves will rest on the wall of the mold inset according to a preferred variant, or are spaced to such an extent that, after reaching the operating temperature, a sufficient surface pressing can be achieved between the sealing sleeve and the wall of the mold inset as a result of the thermal expansion of the entire nozzle.
On the basis of such a solution, the embodiments of the present disclosure are based on further developing the constructions known from DE 20 2008 005 073, in a constructionally simple manner in such a way that its range of use is expanded.
Thus, the present disclosure relates to a hot nozzle for spraying of plastic components. The hot nozzle includes a multipart nozzle body including a tip inset including a tip element having a tip section protruding outwardly beyond a circumferential surface of the multipart nozzle body into a molding plate. The tip section of the tip element is penetrated by a shut-off needle which is movable in a reciprocating manner by a drive. The shut-off needle is movable between a position in which the shut-off needle closes off a feed borehole in the molding plate and a position in which the shut-off needle opens the feed borehole.
Additional disclosure is included in the descriptions below and in the accompanied drawings and claims.
In accordance with the embodiments of the present disclosure, the concepts disclosed in DE 20 2008 005 073, concerning needle shut-off systems are further developed. These further developed needle shut-off systems allow spraying positions very close to rising contours in so-called 0° , tip versions, as shown, for example, in the accompanying FIG. 1, which spraying positions have not been achieved except up until now with the direct hot nozzle spraying in accordance with the present disclosure. On the other hand, the gate in a 90° , tip version, see, for example, the accompanying FIG. 4, is very good. This is as a result of the shearing process during demolding of the article and is further developed into an entirely particle-free gate.
Moreover, the present disclosure includes advantageous mounting of the nozzle.
Notice must be taken that it is known from the state of the art, from EP 1380 400 A1, for example, to penetrate tip elements with shut-off needles. The solution shown in the EP 1 380 400 A1 specification does not allow the production of objects in which the demolding direction corresponds to the injection direction. Moreover, the solution shown in EP 1 380 400 A1 also has a relatively complex drive which is merely suitable for cylindrical hot nozzles. These disadvantages are also remedied by the embodiments according to the present disclosure with simple constructions.
The solutions disclosed in the embodiments of the present disclosure are advantageously suitable for the nozzle bodies and tip insets shown in the accompanying drawings. That is because they can be dismounted in an advantageous manner. Their use is not limited to the kind of tip insets disclosed however. The shut-off needles shown, for example, in FIG. 1 are considered to be used in nozzle bodies with tip elements arranged differently as long as they are provided with a fork-like head which protrudes outwardly over the external jacket of the nozzle bodies.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.